Blast-furnace



(No Model.)

J. M. HARTMAN.

BLAST FURNACE.

No. 460,281. Patented Sept. 29, 1891.

UNITED STATES PATENT OFFICE.

JOHN M. HARTMAN, OF PHILADELPHIA, PENNSYLVANIA.

BLAST-FURNACE.

SPECIFICATION formingpart of Letters Patent No. 460,231, dated September 29, 1891.

Application filed February 24, 1891. Serial No. 382,627, (No model.)

To aZZ whom it may concern:

Be it known that I, JOHN M. IIARTMAN, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Blast-Furnaces, whereof the following is a specification, reference being had to the accompanying drawings.

In said drawings, Figure 1 represents a central vertical section through the lower portion of a furnace embodying my improvements. Fig. 2 is a horizontal section on a plane passing through the axes of the tuyer s; and Fig. 3 is a vertical section, on an enlarged scale, through a portion of the bosh-jacket and the adjacent part of the tuyere-jacket.

In the practical operation of blast-furnaces one of the most serious hinderances to good results is the formation of scaffolds or adhering masses of clinker upon the sides of the furnace. These scaffolds sometimes increase until the stock arches in the furnace and prevents further reduction of the ore, thus necessitating the stoppage of the furnaee, and even when present in less degree they often occasion much irregularity in the quality of the product and great waste of fuel. The primary cause of scaifolding is the tendency of the blast to work up through the center of the furnace, producing an intense combustion in that region, while little or no blast works up along the walls, and consequently, from lack of sufficient heat, the clinker or mass of cinder, fuel, ore, and limestone assumes a sticky character, which tends to make it adhere to the surface of the wall. WVhere thick walls are used for furnaces, the effort has usually been to save them from burning away, and to that intent the blast has been intentionally directed to work toward the center, thus aifordin g the most favorable conditions for scaffolding. Under these circumstances, when it is attempted to destroy the scaffolding by forcing blast up along the walls, they rapidly melt away and require renewal. Moreover, the irregular wasting away of the Walls tends to further enhance the unequal working of the furnace.

In good practice at the present day certain fixed data have become established for practical working of blast-furnaces generally, and but slight variation is found therefrom. Thus,

with a given fuel and a given capacity of the furnace and bosh, the volume of blast per minute proper for the best :.'esults is well known, and, furthermore, the area of the tuyere circle and the normal size of the tuyeres are defined within certain substantially close limits.

My invention avails itself of the conditions thus established, and has for its object the control of the blast in such manner as to prevent the formation of scaffolds due to un equal distribution thereof, certain adjuncts being directed to maintaining unchanged the desirable mode of operation which primarily con stitutes the feature of improvement. Assuming that it is to be applied to a furnace of definite area, with a known fuel and with the volume of blast per minute best adapted to these conditions, my invention consists, broadly, in so proportioning and distributing the tuyeres as without affecting the total blast volume to cause a definite distribution of the blast,' whereby a portion thereof is caused to work up the sides, while the requisite amount is forced toward the center. The subsidiary features of improvement tending to best insure this mode of operation and to maintain the conditions unchanged will be explained hereinafter.

In the drawings, A represents the lower part of the main wall of the furnace, constructed of the usual thickness and in the ordinary manner, and B represents the boshwall. From the point a, opposite to which the mantle (Z is situated, the wall B throughout the bosh and for a short distance above the top thereof is thin, the preferred thickness being from twelve to thirteen inches. This thin wall is bound by a jacket I), between which and the wall is interposed a water-coil E to prevent overheating and consequent burning away of the wall. This jacket 1) extends down to a point immediately above the tuyere-jacket and is bound by a strong band C, placed around the furnace immediately above the level of the tuyere-jacket. Instead, however, of bringingout the lower end of the water-coil E above this band, I continue it down below the same and bring the end 6 outward immediately above the tuyere-j acket F. Furthermore, to prevent the danger of leakage down into the crucible, I form around the inner side of the tuyere-jacket an upwardly-projecting rim f, outside of which is a horizontal or downwardly-inclined surface f. Any water leaking down the coil will thus be deflected outward, instead of ru nning down to chill the hearth.

The tuyeres are indicated by G G and are arranged in a circle in the usual manner and provided with their respective tuyere-pipes I and blast-pipes J, communicating with the bustle-pipe or main blast-passage H. In the instance shown the furnace is provided with six tuyeres, and I prefer to use all of them somewhat above the normal area of nozzle which would be proper for such furnace. I then place in one group of series of tuyeres (preferably in each alternate one of the whole number) reducing-nozzles g. IVith a given pressure the use of such nozzles would of course increase the penetrating power of the blast and force it inward toward the center, While, on the other hand, the use of the tuyeres with large nozzles would tend to make their blast flow up along the walls. If, how- ,ever, both classes were supplied from a common blast-pipe Without modification of the blast therein, the tendency would be for the tuyeres of larger nozzle area to rob those in which the reduced nozzles had been placed, and thus cause an unequal blast distribution, which might prevent proper action in the center of the furnace. To avoid this difficulty, I place in a convenient portion of the several blast-pipes reducers i, which control the blast equally at the pointsindicated, and thus prevent the robbing of the tuyeres which have the small nozzles. The combined areas of the reducers t' of course determine the total volume of the blast per minute, and they should be proportioned accordingly. Under the conditions thus presented it will be seen that scaffolding from the cause above described is effectually prevented, and since the thin walls B, when properly cooled by water circulation, cannot melt away to any substantial extent the otherwise injurious consequences of working the blast up along said walls are avoided and the conditions proper for successful working are maintained.

I have given the above description of the tuyere arrangement and of the combination therewith of the system of reducers in the blast-pipe as typical of what I consider the best embodiment of my invention; but it must be understood that I do not limit myself to the use of directly-alternating tuyeres of different nozzle area, since under some circumstances it may be found desirable to use more of one class than of another, nor do I limit myself to the use of reducers in the blast-pipes, since other methods of insuring the proper distribution of the blast may be substituted therefor without changing the principle of operation.

It must also be understood that while I find it convenient in the firstinstance to make all the tuyeres of substantially larger area than the normal, and then by inserting nozzlepieces in some of them increase the penetrating power of the blast thereof, the said mode of construction is not essential, as the tuyeres themselves maybe originally of different nozzle area, and in defining my invention in the claims hereof I wish it to be understood that under the term normal nozzle area, as applied to the tuyeres of greater penetrating power, I comprehend tuyeres which, under the conditions of use, have outlets of the proper form and dimension to insure the penetration of the blast well into the interior of the furnace.

Having thus described my invention, I claim- 1. In combination with a blast-furnace, a series of tuyeres of substantially normal nozzle area, an alternating series of tuyeres of substantially larger nozzle area, and means, substantially as set forth, whereby a uniform distribution of blast is eifected among said tuyeres.

2. In combination with a blast-furnace, a series of tuyeres of substantially normalnozzle area, an alternating series of tuyeres of substantially larger nozzle area, means, substantially as set forth, whereby a uniform distribution of blast is effected among said tuyeres, and a thin wall extending from the tuyere circle up to the mantle, said wall being provided with a water-coil, as and for the purposes set forth.

3. In combination with ablast-furnace, a series of tuyeres of substantially normal nozzle area, an alternating series of tuyeres of substantially larger nozzle area, a common blastpipe with which said tuyeres respectively conimunicate, and a series of reducers interposed in the line of communication between each tuyere of said series of larger nozzle area and said blast-pipe, whereby an equal distribution of the blast to the tuyeres is insured, substantially as set forth.

JOHN M. HARTMAN.

Witnesses:

JAMES H. BELL, E. Rnnsn. 

